Lawns & Irrigation

Lawns need to be mowed in such a way that no more than one-third of the leaf blade is removed in any one mowing. According to the one-third rule, a lawn mowed at 3 inches will need to be mowed about every seven days. A lawn mowed at 2 inches will need to be mowed every five days. Mowing your lawn at a higher cut will result in a healthier lawn that doesn’t need to be mowed as often.

The optimum mowing height for most lawns is 2 to 4 inches. Turfgrass mowed at the right height will be thicker and need fewer inputs. Mowing above these heights tends to create a less dense turf with coarser leaf blades and a potentially scraggly appearance. Mowing below this height will create weaker turf that will require more inputs like fertilizer, irrigation, and pesticides.

Before Bermuda grass begins to grow in the spring, it is possible to mow the turf slightly shorter than normal to remove dead leaf blades and other debris. This practice reduces shading of emerging plants and helps the soil warm up faster in the spring. The result is a lawn that greens up quicker. The risk in “scalping” your lawn is in cutting off the emerging grass if this practice occurs once the lawn starts to green up. And by allowing sunlight to reach the soil’s surface, you could end up creating better growing conditions for weeds.

Mowing your lawn too low is never a good thing. It results in weaker turf that may require more fertilizer, irrigation, and herbicides to control weeds. In fact, shorter lawns will usually result in more weeds. In addition, mowing too short increases the amount of time and energy required to maintain your lawn. Golf course superintendents select their mowing heights based on turf species, environment, golfer expectations, etc. They have the training necessary to maintain the quality of shorter turfgrass.

In the 1960s, it was commonly believed grass clippings were a major component of thatch, and removing clippings would dramatically slow thatch development. In 1967, researchers at the University of Rhode Island completed and published a detailed study of thatch, showing it was primarily composed of lignin-containing tissues (rhizomes, stolons, and stems) as well as living turfgrass roots. They concluded that leaves and grass clippings do not contribute to thatch buildup. Their findings have since been confirmed by numerous other studies.

Heavy layers of tree leaves shading the grass can smother and kill grass. However, research shows that moderate levels of tree leaves can be mulched without any detrimental effects on the soil or turf and usually leads to improvements in soil structure. The easiest way to dispose of leaves is to simply mow them into the turf. Regular mowing in the fall will chop the leaves up into small pieces and allow them to filter into the turf. Plus, mulching leaves with a mower is easier than raking, blowing, and/or vacuuming them. Removing leaves may still be necessary if copious amounts of leaves accumulate between mowings. If that’s the case, you might try composting them and adding them back into your lawn as a topdressing.